1. Field of the Invention
The present invention relates to a blade breakage and abrasion detecting device, and more specifically, the invention relates to the blade breakage and abrasion detecting device which automatically detects a breakage and an abrasion of a blade of a dicing apparatus.
2. Description of the Related Art
A dicing apparatus which divides a work having a semiconductor device and an electronic element formed thereon into a chip comprises a blade which is rotated at high speed by a spindle, a table which holds the work with suction, X, Y, Z, and θ axes which are the axes of motion changing a relative position of the table and the blade. The dicing apparatus grooves and cuts the work which is held on the table with suction and is relatively moved by each axis with the blade which rotates at high speed.
The blade is gradually abraded because of a work load at the blade when the dicing apparatus processes the work, and the blade is broken at the processing when there is a large work load at the blade. A depth of a groove processed with the blade is changed when the processing is continued with the abraded blade, so a grooving process with a predetermined depth and an assured cutting process can not be performed. Also, it becomes a cause of damaging the workpiece that the processing is continued with the broken blade.
To solve such a problem, a device which detects an amount of an abrasion of a blade by detecting an amount of moving down of the blade when the blade is moved down between a light-emitting unit and a light receiving unit which are provided opposed having a predetermined space in the middle is disclosed in Japanese Patent Application Laid-Open No. 8-164515. In addition, as disclosed in Japanese Patent Application Laid-Open No. 2000-188267, the light-emitting unit and the light receiving unit are provided opposed as sandwiching the rotating blade and the breakage of the blade is detected by detecting the change of the amount of the light received at the light receiving unit.
However, it is necessary to suspend the processing of the work, move the blade to the abrasion amount detecting device provided the position separated from the table, and move up and down the blade, in order to detect the abrasion amount of the blade with the abrasion amount detecting device of Japanese Patent Application Laid-Open No. 8-164515, thereby a processing efficiency is decreased. The light transmitted to a light-emitting area of the light-emitting unit of a blade breakage detector is small and round at the abrasion amount detecting device of Japanese Patent Application Laid-Open No. 2000-188267, so the peak of the detection sensitivity is narrow with the condition and it is necessary to adjust the height depending on the outstanding length of the blade.
Therefore, Japanese Patent Application Laid-Open No. 2006-310396 discloses a blade breakage and abrasion detecting device including the light-emitting unit and the light receiving unit provided near by the side of the blade of the dicing apparatus. The light-emitting area of the light-emitting unit and the light receiving area of the light receiving unit have the length equal to or longer than the length of the blade which is outstanding from a flange, and are rectangular shape areas having a longer side toward the rotation center of the blade.
It is possible to detect the blade breakage and abrasion by detecting the change of the amount of light received with the light receiving area of the light receiving unit according to the blade breakage and abrasion detecting device. At this time, the light-emitting area of the light-emitting unit and the light receiving area of the light receiving unit have the length equal to or longer than the outstanding length of the blade toward the rotation center of the blade, so there is no need to adjust the positions of the light-emitting unit and the light receiving unit according to the outstanding length of the blade. Moreover, there is unnecessary to move the blade to the abrasion amount detecting device because it is possible to calculate the abrasion amount based on the increased amount of the received light. Additionally, it is possible to detect the blade breakage according to the rapid change of the amount of the received light during processing and the abrasion amount of the blade according to the increased amount of the received light even during processing.